We add the glue code that sets up a dma_ops structure with thexen_swiotlb_* functions. The code turns on xen_swiotlb flagwhen it detects it is running under Xen and it is eitherin privileged mode or the iommu=soft flag was passed in.

It also disables the bare-metal SWIOTLB if the Xen-SWIOTLB hasbeen enabled.